Axle spindle and method for making the same

Abstract

A spindle for an axle is capable of supporting a vehicle wheel which is rotatably mounted thereon at a pair of axially disposed bearings. The spindle includes a cylindrical portion at its outer end which serves as an outer bearing mounting region while the portion of the spindle inwardly of the outer bearing mounting region is provided a frusto-conical outer surface. The inner wheel bearing has an inner race with a frusto-conical inner surface so that the frusto-conical outer surface of the spindle will serve as the inner bearing mounting region. Such a spindle is preferably cold formed from a hollow tubular blank having a generally uniform external diameter and wall thickness.

I claim: 
     
       1. A method of forming an axle spindle and bearing assembly for a vehicle wheel of the type to be utilized in heavy duty truck and trailer applications, said vehicle wheel being subjected to normal operating forces which require a pair of tapered roller bearings for its support and produce primary stresses in said axle spindle at an inwardly position tapered roller bearing of said pair, said method comprising: providing a hollow tubular blank having a central axis, a generally uniform external diameter and wall thickness and a first open end; reducing said tubular blank at a first region including said first end concentric with said central axis to provide a first diameter therefor; forming a transition region with a relatively uniform thickness having a frusto-conical outer surface between said first region and a portion of said tubular blank which is free of said reducing and remote from said first end; machining an area of said first region and an area of said frusto-conical outer surface for respectively receiving first and second tapered roller bearings of said pair thereon for rotatably supporting said wheel on said spindle, said second tapered roller bearing being said inwardly positioned tapered roller bearing of said pair; providing said first tapered roller bearing with an inner race having a cylindrical inner surface matching said area of said first region and providing said second tapered roller bearing with an inner race having a frusto-conical inner surface matching said area of said frusto-conical outer surface to provide the only contact between said second tapered roller bearing and said axle spindle. 
     
     
       2. The method as set forth in claim 1, wherein said steps of reducing at said first region and forming said transition region are accomplished by circumferentially cold working said tubular blank. 
     
     
       3. The method as set forth in claim 2, wherein a first step of cold forming includes forming a portion of said transition region remote from said first end and reducing the said blank at said first region and the remainder of said transition region to provide an interim diameter therefor which is greater than said first diameter and a second step of cold forming to complete the formation of said first region and said remainder of said transition region.